Apparatus for grinding and sorting powders.



(LT. FULLER APPARATUS FOR GRINDING AND SOR'VIING I'JOWDEES. APPLICATION FILED we. 19, 1907.

ifilfimfi I 'Patnted 0011.22, 1912,

Z'ZHZ'SISZS" 177022750, 60ml Til 55%? YWM r srarns ur op n CARL T. FULLER, 0F SCHENEGTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

Specification of Letters Patent.

Patented Oct. 22,1912.

Application filed August 19, 1907. Serial No. 389,314.

To all whom it may concern:

Be it known that I, CARL T. FULLER, a citizen of the United States, residing at- Schenectady, county of Schenectady, State of New York, have invented certain new and usefulImprovements in Apparatus for Grinding and Sorting Powders, of which the following is a specification.

According to my present invention, a

powdered material is inclosed in a chamber and there subjected to a jet of gaseous fluid operating to grind the particles of the powder one on anotherand to float ofl andcarry away the lighter particles, depositing them in settling chambersso arranged that the powder 'is sorted according to the size of the particles. The apparatus for effecting this result is suitable for use with a great variet 1 of powdered materials, but I have applied it with particular success to the grinding andsorting of tungsten and its oxids. These materials are nowused eX- tensively in the manufacture of tungsten lamp filaments and other refractory conductors requiring a raw material very fine and uniform. I will explain my apparatus as used in the grinding of tungsten trioxid, audits use for other purposes will be obvious. v

In the drawing accompanying this specification and forming a part thereof, Figure 1 is a sectional elevation of a grinding chamber, and Fig. 2 is an elevation, partly chambers. The upper or larger end of the grinding chamber is closed by a board 4 secured in place inany suitable manner as bymeans of the bolts 5. I prefer to make this grinding chamber flaring in order that the velocity of the projected jet of air or other fluid may decrease progressively from the inlet 2 to the outlet 3.

The grinding chamber may be two or .three feet in height and will then take a charge of say 3000 grams of tungsten trioxid. The charge is placed loosely 1n the flaring glass tube 1 and then subjected to the action of a jet of airforced in through an inlet 2 at a pressure of say 15 pounds to the square inch.

In order to vary the direction of the incoming air and to insure the best distribution thereof through the charge, I place a weighted ball 6 immediately over the inlet 2 in such a way that it tends to float about or move around on the inlet and thus serve as a battle to shift the direction of the incoming jet from one side to another. This shifting jet of air l reeps the ntire charge in rapid movement.

The continuous and violent movement of the powder serves to grind the particles against one another, thereby breaking up the larger particles into bodies which can float away easily through the outlet 3.

A battery of grinders may be operatedsimultaneously, as shown in Fig. 2, in which 7, 8', 9 and 10 are similar grinding chambers supplied from the air pipe 11, and discharging respectively through the tubes l2, 13, 14 and 15 into a series of settling chambers arranged in a cupboard shaped box 16. This cupboard 16 may conveniently have a height of six or eight feet and be divided by horizontal partitions 17 into a plurality of chambers 18, 19, 20, etc., of progressively increasing volume. When the air blast enters the cupboard at the bottom, as shown in Fig. 2, it passes across the bottom and then up through holes in the lowerpartition 17 and thereafter follows a zig-zag path upward throughgthe' several chambers 18, 1-9, 20, etc. Inasmuch as these chambers progressively increase in volume the velocity of air blast will progressively decrease and the fine particles of dust or powder carried idsnspension will gradually settle outon the shelf 17. The coarser powderwill be near the bottom of the cupboard and the finer powder near the top.

Inasmuch as the air blast passing through the uppef compartment-of the cupboard may carry very considerable quantities of the oxid, and this. of the finest and therefore most valuable quality, I provide the upper compartment with an outlet or discharge pipe 21 leading downward and discharging into a closed room 22. I prefer to make this room relatively large, say twenty feet on a side, and to lineit with a smooth material from which the finely divided powder can readily be collected. Theroom may be provided with an outlet 23 discharging into the open air.

When the grinders 7, 8, 9 and 10 are charged with tungsten trioxid and operated by air jets under a pressure of say pounds to the square inch, the oxid powder seems to boil and swirl about in the grindingchamhers and gradually passesover into the cupboard where a considerable part is deposited for various purposes orcan be returned to the grinders and again vsubjected to the grinding action, and thus broken up into fine particles which will pass over into the final settling chamber. By repeatedly charging the grinders from material taken from the lower shelves of the cupboard, I

can gradually convert the powder into very fine form and pass it. over in the final settling chamber.

As previously-stated, the use of, this im-. proved apparatus is not limited to the treatment of tun sten trioxid, but is of use in connection-With many other materials. Inasmuch, however, as tungsten trioxid is, according to ordinary methods, one of the most difiicult materials to grind, it' serves well to illustrate the application of my invention.

a If the grinding of tungsten .trioxid. is attempted in a ball mill or other similar grinder it presses together into compact nodules, and also cakes on the balls-and on. the walls of the chamber, but it undergoes no apparent grinding. In fact, material so treated packs together and becomes utterly useless for lamp filament manufacture. The material produced by the. use of the apparatus disclosed herein is very light and flufiy and when reduced with hydrogen or other suitable reducing agent yields an extremely fine tungsten powder, well adapted for the production of lamp filaments according to any one of several methods.

These finer particles are so shifting and varying the 2 direction Witnesses:

What I claim as new and desire to secure by Letters Patent ofihe United States, is,

1. The combination of a grinding channber in which powdered material may be placed, means for discharging a jet of gas eous fluid into said powder within the cham' ber and movable means for automatically and progressively shifting the position and direction of the'jet.

2. The combination of a grinding chan through which a gaseous medium may be introduced into said chamber in 'a jet of high velocity to exert a grinding action on the powdered material, and movable means by which the direction in said chamber of the incoming jet is constantly varied.

' 4. As a means for grinding powder, a flaring chamber in which the powder may be introduced from the top, means forv discharging a jet of gaseous .fiuid into the bottom of said chamber to produce a grinding action of the seveial particles of said pow-.

der one on another, and a ball in the path of the incoming jet and movable thereby,-

5. The combination of a grinding chard-- ber into which powdered material may be introduced, means'for subjecting said material to the grinding action of a jet of pure air and a moving object between the incoming jet of pure air and the powdered mate rial for varying the direction of play of said jet in said chamber.

6. The combination with a closed upwardly -flaring gr;inding chamber of means for introducing an upwardly jetting, blast of gaseous fluid at the bottom thereof and In witness whereof I- have hereunto setmy -hand this 17th deg of August, 1907. v

' ARL T. FULLER.

BENJTimN B. HULL, IIELEN Onronn.

Gopies of this patent may be obtained for five cents each, by addressing the Commissioner of IPatents,

Washington, D. 0.

,means in the path of said blast and brought 

